Revert "drm/i915/display: move dmc_firmware_path to display params"

This reverts commit 0d82a0d6.

The commit failed to take into account that the parameter duplication
and debugfs for char * parameters were subtly different between i915
core and display, and caused the DMC and PM to be disabled. Moreover,
the patch was pushed with failing CI results. Revert, and get back to
the drawing board.
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/display/intel_display_params.c

@@ -27,9 +27,6 @@ static struct intel_display_params intel_display_modparams __read_mostly = {
  * debugfs mode to 0.
  */
 
-intel_display_param_named_unsafe(dmc_firmware_path, charp, 0400,
-	"DMC firmware path to use instead of the default one");
-
 intel_display_param_named_unsafe(vbt_firmware, charp, 0400,
 	"Load VBT from specified file under /lib/firmware");
 

drivers/gpu/drm/i915/display/intel_display_params.h

@@ -24,7 +24,6 @@ struct drm_i915_private;
  *       debugfs file
  */
 #define INTEL_DISPLAY_PARAMS_FOR_EACH(param) \
-	param(char *, dmc_firmware_path, NULL, 0400) \
 	param(char *, vbt_firmware, NULL, 0400) \
 	param(int, lvds_channel_mode, 0, 0400) \
 	param(int, panel_use_ssc, -1, 0600) \

drivers/gpu/drm/i915/display/intel_dmc.c

@@ -927,7 +927,7 @@ static void dmc_load_work_fn(struct work_struct *work)
 
 	err = request_firmware(&fw, dmc->fw_path, i915->drm.dev);
 
-	if (err == -ENOENT && !i915->display.params.dmc_firmware_path) {
+	if (err == -ENOENT && !i915->params.dmc_firmware_path) {
 		fallback_path = dmc_fallback_path(i915);
 		if (fallback_path) {
 			drm_dbg_kms(&i915->drm, "%s not found, falling back to %s\n",
@@ -1034,14 +1034,14 @@ void intel_dmc_init(struct drm_i915_private *i915)
 		dmc->max_fw_size = BXT_DMC_MAX_FW_SIZE;
 	}
 
-	if (i915->display.params.dmc_firmware_path) {
-		if (strlen(i915->display.params.dmc_firmware_path) == 0) {
+	if (i915->params.dmc_firmware_path) {
+		if (strlen(i915->params.dmc_firmware_path) == 0) {
 			drm_info(&i915->drm,
 				 "Disabling DMC firmware and runtime PM\n");
 			goto out;
 		}
 
-		dmc->fw_path = i915->display.params.dmc_firmware_path;
+		dmc->fw_path = i915->params.dmc_firmware_path;
 	}
 
 	if (!dmc->fw_path) {

drivers/gpu/drm/i915/i915_params.c

@@ -108,6 +108,9 @@ i915_param_named_unsafe(guc_firmware_path, charp, 0400,
 i915_param_named_unsafe(huc_firmware_path, charp, 0400,
 	"HuC firmware path to use instead of the default one");
 
+i915_param_named_unsafe(dmc_firmware_path, charp, 0400,
+	"DMC firmware path to use instead of the default one");
+
 i915_param_named_unsafe(gsc_firmware_path, charp, 0400,
 	"GSC firmware path to use instead of the default one");
 

drivers/gpu/drm/i915/i915_params.h

@@ -51,6 +51,7 @@ struct drm_printer;
 	param(int, guc_log_level, -1, 0400) \
 	param(char *, guc_firmware_path, NULL, 0400) \
 	param(char *, huc_firmware_path, NULL, 0400) \
+	param(char *, dmc_firmware_path, NULL, 0400) \
 	param(char *, gsc_firmware_path, NULL, 0400) \
 	param(bool, memtest, false, 0400) \
 	param(int, mmio_debug, -IS_ENABLED(CONFIG_DRM_I915_DEBUG_MMIO), 0600) \

drivers/gpu/drm/xe/xe_device_types.h

@@ -524,6 +524,9 @@ struct xe_device {
 		unsigned int fsb_freq, mem_freq, is_ddr3;
 		u8 vblank_enabled;
 	};
+	struct {
+		const char *dmc_firmware_path;
+	} params;
 
 	void *pxp;
 #endif